[kvm-unit-tests PATCH v2 2/5] s390x: css: simplifications of the tests

[Pierre Morel <pmorel@xxxxxxxxxxxxx>]

In order to ease the writing of tests based on:
- interrupt
- enabling a subchannel
- using multiple I/O on a channel without disabling it

We do the following simplifications:
- the I/O interrupt handler is registered on CSS initialization
- We do not enable again a subchannel in senseid if it is already
  enabled
- we add a css_enabled() function to test if a subchannel is enabled

Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx>
---
 lib/s390x/css.h     |  1 +
 lib/s390x/css_lib.c | 37 ++++++++++++++++++++++----------
 s390x/css.c         | 51 ++++++++++++++++++++++++++-------------------
 3 files changed, 56 insertions(+), 33 deletions(-)

diff --git a/lib/s390x/css.h b/lib/s390x/css.h
index 1e317d1..fa8775f 100644
--- a/lib/s390x/css.h
+++ b/lib/s390x/css.h
@@ -278,6 +278,7 @@ int css_enumerate(void);
 
 #define IO_SCH_ISC      3
 int css_enable(int schid, int isc);
+bool css_enabled(int schid);
 
 /* Library functions */
 int start_ccw1_chain(unsigned int sid, struct ccw1 *ccw);
diff --git a/lib/s390x/css_lib.c b/lib/s390x/css_lib.c
index 88aa7a1..5426a6b 100644
--- a/lib/s390x/css_lib.c
+++ b/lib/s390x/css_lib.c
@@ -180,6 +180,31 @@ out:
 	return schid;
 }
 
+/*
+ * css_enabled: report if the subchannel is enabled
+ * @schid: Subchannel Identifier
+ * Return value:
+ *   true if the subchannel is enabled
+ *   false otherwise
+ */
+bool css_enabled(int schid)
+{
+	struct pmcw *pmcw = &schib.pmcw;
+	int cc;
+
+	cc = stsch(schid, &schib);
+	if (cc) {
+		report_info("stsch: updating sch %08x failed with cc=%d",
+			    schid, cc);
+		return false;
+	}
+
+	if (!(pmcw->flags & PMCW_ENABLE)) {
+		report_info("stsch: sch %08x not enabled", schid);
+		return false;
+	}
+	return true;
+}
 /*
  * css_enable: enable the subchannel with the specified ISC
  * @schid: Subchannel Identifier
@@ -229,18 +254,8 @@ retry:
 	/*
 	 * Read the SCHIB again to verify the enablement
 	 */
-	cc = stsch(schid, &schib);
-	if (cc) {
-		report_info("stsch: updating sch %08x failed with cc=%d",
-			    schid, cc);
-		return cc;
-	}
-
-	if ((pmcw->flags & flags) == flags) {
-		report_info("stsch: sch %08x successfully modified after %d retries",
-			    schid, retry_count);
+	if (css_enabled(schid))
 		return 0;
-	}
 
 	if (retry_count++ < MAX_ENABLE_RETRIES) {
 		mdelay(10); /* the hardware was not ready, give it some time */
diff --git a/s390x/css.c b/s390x/css.c
index 18dbf01..d4b3cc8 100644
--- a/s390x/css.c
+++ b/s390x/css.c
@@ -56,36 +56,27 @@ static void test_enable(void)
  * - We need the test device as the first recognized
  *   device by the enumeration.
  */
-static void test_sense(void)
+static bool do_test_sense(void)
 {
 	struct ccw1 *ccw;
+	bool success = false;
 	int ret;
 	int len;
 
 	if (!test_device_sid) {
 		report_skip("No device");
-		return;
+		return success;
 	}
 
-	ret = css_enable(test_device_sid, IO_SCH_ISC);
-	if (ret) {
-		report(0, "Could not enable the subchannel: %08x",
-		       test_device_sid);
-		return;
-	}
-
-	ret = register_io_int_func(css_irq_io);
-	if (ret) {
-		report(0, "Could not register IRQ handler");
-		return;
+	if (!css_enabled(test_device_sid)) {
+		report(0, "enabling subchannel %08x", test_device_sid);
+		return success;
 	}
 
-	lowcore_ptr->io_int_param = 0;
-
 	senseid = alloc_io_mem(sizeof(*senseid), 0);
 	if (!senseid) {
 		report(0, "Allocation of senseid");
-		goto error_senseid;
+		return success;
 	}
 
 	ccw = ccw_alloc(CCW_CMD_SENSE_ID, senseid, sizeof(*senseid), CCW_F_SLI);
@@ -129,16 +120,21 @@ static void test_sense(void)
 	report_info("reserved 0x%02x cu_type 0x%04x cu_model 0x%02x dev_type 0x%04x dev_model 0x%02x",
 		    senseid->reserved, senseid->cu_type, senseid->cu_model,
 		    senseid->dev_type, senseid->dev_model);
+	report_info("cu_type expected 0x%04x got 0x%04x", (uint16_t)cu_type,
+		    senseid->cu_type);
 
-	report(senseid->cu_type == cu_type, "cu_type expected 0x%04x got 0x%04x",
-	       (uint16_t)cu_type, senseid->cu_type);
+	success = senseid->cu_type == cu_type;
 
 error:
 	free_io_mem(ccw, sizeof(*ccw));
 error_ccw:
 	free_io_mem(senseid, sizeof(*senseid));
-error_senseid:
-	unregister_io_int_func(css_irq_io);
+	return success;
+}
+
+static void test_sense(void)
+{
+	report(do_test_sense(), "Got CU type expected");
 }
 
 static void css_init(void)
@@ -146,8 +142,19 @@ static void css_init(void)
 	int ret;
 
 	ret = get_chsc_scsc();
-	if (!ret)
-		report(1, " ");
+	if (ret) {
+		report(0, "Could not get CHSC Characteristics");
+		return;
+	}
+
+	ret = register_io_int_func(css_irq_io);
+	if (ret) {
+		report(0, "Could not register IRQ handler");
+		return;
+	}
+	lowcore_ptr->io_int_param = 0;
+
+	report(1, "CSS initialized");
 }
 
 static struct {
-- 
2.17.1